I visited Alexandra Sports in Portsmouth yesterday and have to report that there shoe fitting service is brilliant. They have 5 or 6 trained staff who will take as much time as it needs to fit a pair of shoes.

I went in specifically for a pair of Inov-8s, but if you are just going in to get a pair of running shoes they will get the best fit of the hundreds they stock!

The only downside is that they only do running shoes.....

I'll second any good reports of Alexandra Sports! It's about three years since I moved up north now, but this shop supported my running for many years. They got me through a marathon, and various other races, got me into off road running, and nothing was ever too much trouble for them. As CS says, they go to great lengths to match you up with the right shoes and other bits of kit, and are well worth a visit for any Hants/west Sussex based runners.